2. • What are earthquakes?
• What conditions cause earthquakes?
• What are some vocabulary words
associated with earthquakes?
• How are earthquakes measured?
• What are the results of earthquakes?
• What does an earthquake feel like?
5. http://earthquake.usgs.gov/learn/kids/
Latest Quakes
http://earthquake.usgs.gov/learn/today/
Today in Earthquake History
http://earthquake.usgs.gov/earthquakes/state
s/georgia/history.php
Georgia Earthquakes
Click Past 8-30 days, too
6. 1. The definition of an earthquake is… a
sudden release of tectonic stress along a
fault line. They can also result from
volcanic activity. Earthquakes create
vibrations that cause the breaking of
rocks, violent shaking of Earth’s
crust, and destruction of buildings.
2. These vibrations move in all directions
through the earth. They begin at a point
along a fault.
3. A fault is a break in earth’s crust.
7. • The earth’s crust is constantly
experiencing pressure from forces
within and around it. This pressure
builds up over time, and eventually
causes the crust to break. This
becomes a fault.
• Let’s experience it…
8. • Faults are divided into three main groups (WORKSHEET
TIME!):
4. Normal fault - when two plates are moving apart and one
side of the fracture moves below the other; (caused by
tension and occur at divergent boundaries!)
5. Reverse fault or thrust fault - when two plates collide
and one side of the fracture moves on top of another
(caused by compression and occur at convergent
boundaries!) A thrust fault has the same sense of motion as
a reverse fault, but with the dip of the fault plane at less than
45 .
6. Strike-slip or Lateral (football plays) - when two plates
slide past each other horizontally. (caused by shear
stress or shearing and occur at transform boundaries!)
*Most common fault to cause an earthquake.*
9. 7. Focus: An earthquake begins along a
fault (a crack in the earth’s surface) at a
point called the focus.
8. Epicenter: Directly above the focus is
a point on the earth’s surface called the
epicenter.
*E comes before F so the epicenter is
above the focus.*
11. 9. Seismic Waves
When the fault ruptures with a sudden
movement energy is released that has
built up over the years. The energy
from an earthquake is released in the
form of vibrations called 'seismic
waves'… earthquakes! It is actually
when these seismic waves reach the
surface of the earth that most of the
destruction occurs, which we associate
with earthquakes.
12. Earthquake
Waves
10. Primary Wave (P-Wave)
Three Main Types:
•First set of waves
•Move side to side
•FASTEST wave
11. Secondary Wave (S-Wave)
•Second set of waves
•Also, called a Shear Wave
•Move up and down
•Travel slow
12. Surface Wave
•Move up and down & side to side
•MOST DANGEROUS
•SLOWEST Wave
13.
14. 13. Magnitude is a number that characterizes the relative
size of earthquakes & is proportional to energy released
16. What Kind Of Damage Do Earthquakes Cause?
Earthquakes can also cause landslides, sudden
eruptions as in the case of a hot lava flow from a volcano
or giant waves called tsunamis. Sometimes new land
mass are also formed. Such earthquakes are attributed
with the creation of the greatest undersea mountain
range and the longest land mountain range. Liquefaction
is also a danger of earthquakes in areas where the soil is
wet or where water is nearby.
14. Aftershocks are the small earthquakes that
follow a larger one. They are the minor
readjustments along the fault after a quake. With
time, these small quakes get less and less
intense.
17. 15.
Liquefaction-
When water-saturated soil is shaken in an
earthquake, it can behave like a liquid. This is
called liquefaction.
• When the soil acts like a liquid, it can cause great
damage to the buildings standing on it.
• Liquefaction is what happens to the wet sand at
the beach. The sand is hard when you stand on
it, but becomes liquid-like when you stick your
toes down in it.
*See the cornstarch demonstration*
19. Folding
17. Folding-the bending of the rock layers from
stress is called folding.
18. Anticline-folds that arch up
19. Syncline-folds that sink down
20. 20. Elastic Deformation
- Leads to earthquakes; it is the sudden return
of elastically deformed rock to its undeformed
shape
• Think of it as a stretched-out rubber band.
You can only stretch it so far before it breaks.
When it breaks, it releases energy. Then the
unbroken pieces return to their original shape.
• (from the textbook)
21.
22.
23. • 9.5 Chile, May 22, 1960
• 9.2 Indian Ocean (Sumatra tsunami) Dec 26,2004
• 9.2 Prince William Sound, Alaska, March 28, 1964
• 9.1 Andreanof Islands, Aleutian Islands, Pacific,
• March 9, 1957
• 9.0 Great East Japan Earthquake and Tsunami, March 13, 2011
• 9.0 Kamchatka, Russia, November 4, 1952
• 8.8 Off the Coast of Ecuador, January 31, 1906
• 8.7 Rat Islands, Aleutian Islands, Pacific,
• February 4, 1965
• 8.6 India-China Border, August 15, 1950
• 8.5 Kamchatka, Russia, February 3, 1923
• 8.5 Banda Sea, Indonesia, February 1, 1938
• 8.5 Kuril Islands, Pacific, October 13, 1963
• http://www.bbc.co.uk/news/world-asia-pacific-12725646
28. • In the lower 48 states, there is a tie
between the February 1812, New
Madrid, Missouri earthquake and the
January 1857, Fort Tejon, California
earthquake--both magnitude 7.9--for the
strongest earthquake recorded.
29. • Generally, during an earthquake you
first will feel a swaying or small jerking
motion, then a slight pause, followed
by a more intense rolling or jerking
motion. The duration of the shaking
you feel depends on the earthquake's
magnitude, your distance from the
epicenter, and the geology of the
ground under your feet.
30. • For minor earthquakes, ground shaking
usually lasts only a few seconds.
• Strong shaking from a major earthquake
usually lasts less than one minute. For
example, shaking in the 1989 magnitude 7.1
Loma Prieta (San Francisco) earthquake lasted
15 seconds;
• For the 1906 magnitude 8.3 San Francisco
earthquake it lasted about 40 seconds.
• Shaking for the 1964 magnitude 9.2 Alaska
earthquake, however, lasted three minutes.